Where metallic tape is used in some manufacturing operation the tape is customarily paid from a flat roll or from a spool and when the roll is exhausted the entire operation must be shut down until a new roll can be introduced and the leading end of a fresh tape spliced onto the trailing end of the tape in use. A typical operation requiring metallic tape of a type which is the subject of the present invention occurs in electric cable manufacture where a thin copper tape is continuously applied as electrical shielding over a cable core. In this application the tape is folded around the core during the extrusion of the cable jacket and any interruption of the tape supply will cause a shutdown of the entire extrusion process or a discontinuity in the cable.
Mechanical means have been commercially available for making overlapped soft-solder splices in copper cable tapes, but such splices have the disadvantage of a double thickness of tape plus the thickness of the solder layer at the area of overlap. This increased thickness, and the resulting tape stiffness, may prevent proper folding of the tape around the cable core and/or cause the tape to become jammed in the folding or extrusion apparatus. Prior to the present invention no commerically practical method had been known for making reliable butt splices in cable shielding tapes. As a consequence, cable manufacturers having the most advanced manufacturing equipment and development facilities have been forced to the expedient of paying one length of shielding tape after another without splicing the tapes together. They are then required to mark the points in the cable where tape discontinuities occur and to cut the cable at these points.